Preheat your oven to 350°F (175°C).

In a skillet over medium heat, crumble and cook the beef sausage until browned, about 8-10 minutes. Drain any excess grease.

In a large bowl, whisk together the eggs, cream cheese, milk, salt, and pepper. Incorporate the sausage after it has cooled slightly.

Stir in the shredded cheese and mix well. If desired, fold in diced vegetables at this step.

Pour the mixture into a greased 9x13 inch casserole dish, spreading it evenly.

Place the dish in the preheated oven and bake for 25 to 30 minutes, or until the edges are bubbly and the center is set.

Once baked, allow the casserole to cool for a few minutes before cutting into squares.